PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 75

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

DU
DD
3.6.2
The Command/Indication channels carry real-time control and status information over
the IOM
3.6.2.1
The active C/I Channel of the IEC-Q is available in all operational modes. The channel
consists of four bits in each direction. Activation and deactivation of the IEC-Q is always
controlled via the active C/I Channel. The C/I codes going to the IEC-Q are called
’commands’, those originating from it are referred to as ’indications’.
The IEC-Q verifies C/I commands with a double last-look criterion, i.e. a new command
will be recognized as valid only after it has been correctly detected by the IEC-Q for two
consecutive IOM
If the microprocessor interface is not being used for controlling the C/I Channel,
commands have to be applied continuously on DIN until the command is validated by the
IEC-Q and the desired action has been initiated. Afterwards the command may be
changed which would initiate another action by the IEC-Q. An indication is issued
permanently by the IEC-Q on DOUT until a new indication needs to be forwarded.
In stand-alone mode the active C/I Channel is controlled by an external device, e.g. the
ICC, 3PAC, IPAC or ISAR, EPIC
In µP mode the active C/I Channel can either be controlled by an external device or via
the microprocessor interface. For a description on how to access the active C/I Channel
via the µP-interface please refer to chapter "Microprocessor Access to IOM
Channels", page 97.
All available C/I codes of the IEC-Q are listed and explained in "C/I Channel Codes",
page 224.
Semiconductor Group
S/G-bit
A/B-bit
TBA0-2:
®
-2 interface.
IOM
Active C/I Channel
E
1
®
-2 Command / Indication Channels
®
-2 frames.
(Stop/Go), available to a connected HDLC controller to determine if
it can access the D-channel (S/G = 1: stop, S/G = 0: go).
(available/blocked), supplementary bit for D-channel control.
(A/B = 1: D-channel available, A/B = 0: D-channel blocked).
TIC Bus Address
E
1
BAC
S/G
®
, ELIC
®
TBA2
.
A/B
75
TBA1
1
TBA0
Functional Description
1
Data Sheet 01.99
1
1
PEB 2091
PEF 2091
1
1
®
-2